Electromagnetic relay with sliding leaf spring movable contacts



Nov. 23, 1965 E. M. MILLER ETAL 3,219,781

ELECTROMAGNETIC RELAY WITH SLIDING LEAF SPRING MOVABLE CONTACTS FiledJune 10, 1963 p 19 n 1 195 2 B x D 1 /9 0 I a t 7 llllllllllll l'l 5 5/INVENTOR. (XE-RR) 0. /f 1.15) 4 50651105 A4. M14 L ER AT K1 1 UnitedStates Patent 3,219,781 ELECTROMAGNETIC RELAY WITH SLIDING LEAF SPRINGMOVABLE CONTACTS Eugene M. Miller, Crystal Lake, 111., and Jerry O.Kelley,

Lake Ozark, Mo assignors, by direct and mesne assignments, to RadonCorporation, a corporation of Illinois, and Donald J. Moloney &Associates, Inc., a corporation of Illinois Filed June 10, 1963, Ser.No. 286,634 Claims. (Cl. 200-104) The principal object of theimprovements disclosed is the provision of a contact system usefulgenerally for switching purposes but especially adapted to use in anelectromagnetic relay of the solenoid type in which the driving oractuating means is a member, such as a solenoid plunger, which moveslinearly.

The contact system is characterized chiefly in the fact that it includesa set of movable contacts in the form of elongated, bowed fingers ofrelatively great flexibility which are grouped about the linearlymovable driving or actuating member so that their principal motion is inthe general direction of displacement paralleling the axis ofdisplacement of the driving member, but the contacting ends of suchfingers bear against a panel carrying stationary contacts arrangedcircumambiently and radially about such axis and the fingers flex so asto glide over the panel in a changed direction which is radial, and inso doing to wipe over the stationary contacts in advancing or retreatingfrom one concentric ring of such contacts to another.

The disclosed contact system has the advantage that it is especiallyeffective for use with the printed circuit type of contact chemically,electrolytically, or mechanically laid down in more or less flushrelation with the panel carrying the stationary array of contacts, byreason of which a large number of contacts can be employed at smallexpense in a small space and easily wired.

The novel construction makes use of the relatively more etlicientsolenoid electromagnet and can be made in large or miniatureembodiments, and both the movable and stationary contact components maybe pre-wired before assembly with the electromagnetic drive or actuatingmeans.

Additional aspects of novelty and utility pertain to details of theconstruction and operation of the embodimerit described for purposes ofillustration hereafter in view of the annexed drawing in which:

FIG. 1 is a perspective view of a relay embodying the new contactarrangement;

FIG. 2 is a vertical section looking in the direction of lines 22 ofFIG. 1;

FIG. 3 is an exploded perspective of the moving contact assembly;

FIG. 4 is a cross-sectional deatil of the contact retaining cap;

FIG. 5 is a fragmentary cross-sectional detail of a modified contactpanel structure;

FIG. 6 is a view similar to FIG. 5 with parts differently positioned.

While the novel contact means may be used with any kind of actuatorarranged to impart linear reciprocatory motion to the moving contactmeans, the improvements have a particularly important use in conjunctionwith a soTenoid type relay such as depicted in FIGS. 1 and 2, and whichin the illustrative form shown comprises a U-shaped ferromagnetic framepiece 10 having a solenoid winding 11 set in the yoke thereof.

Within the bore of the solenoid is the usual magnetically-attractableplunger 12 normally elevated by a spring 13 and attracted inwardly ofthe bore on energization of the winding with the heel of the plungerstriking a small stop plug '14 (FIG. 2).

Secured by suitable means, such as screws 16, is a contact panel 18 ofinsulating material carrying an array of stationary contacts exposed onthe upper face thereof, such contacts being preferably of theprinted-circuit variety embedded in the panel with only their uppermostsurface areas exposed in the plane of the upper face of the panel.

The stationary contacts are arranged concentrically of a center in thepanel which coincides with the center of the bore of the solenoid andthe axis of the plunger working therein; and said contacts each includeportions lying principally in radial paths relative to said center andaxis. Thus, in FIG. 1, contacts 1'9 lie in an inner ring and havecontact areas elongated along a radius Z with an offset connectionportion 19A continuing outwardly toward the edge of the panel toterminate in soldering eyelets 193.

The contacts 20 which lie in the next outer ring also lie along theaforesaid radius Z but continue directly to the panel edge into theircorresponding connecting terminals or soldering eyelets 20B. Thus, allcircuit connections to the stationary contacts may be made to theterminal eyelets around the periphery of the contact panel, as will beapparent from the fragmentary wire connections 23 shown, whichillustrates pre-wiring.

The movable contact means is carried on the upper exposed end regions ofthe solenoid plunger which is long enough to project through the centralopening 18A of the contact panel a substantial distance above the upperface thereof.

An insulated contact-carrying means is mounted on the upper end of theplunger and preferably comprises the parts particularly seen in FIG. 3,including a molded seat member 25 of cylindrical configuration havingspaced about its outer periphery a plurality of contact-seating groovesor channels 26 defined between ribs 27 spaced apart to receive one ofthe elongated spring contact fingers 30 in the bottom thereof.

Each contact spring 30 has an upper terminal end portion 31 bentoutwardly to project beyond the periphery of the cylindrical seat so asto be exposed for soldered connection with a conductor or jumper. Thecontact fingers are bowed in a direction outwardly of the plunger, andtheir lower free ends are given a form to provide contact wipers 32adapted to glide along the surface of the stationary contact panel.

The contact seating member 25 is molded with a central bore having aslight taper to fit closely with a corresponding seating taper on theupper end of the solenoid plunger, and the several spring contactfingers are secured in their respective seats by a molded annular cap 35having a plurality of grooves 36 and ribs 37 about its inner peripheryinterfitting with the ribs and grooves on the seat, whereby the contactfingers are locked into their seating grooves or channels with theirrespective terminal ends 31 projecting from beneath the cap, as seen inFIGS. 1 and 2. The contact assembly is fixed in position by means of acap washer 37 and a screw 38 threading into the end of the plunger.

Means for preventing the contact assembly from rotating about the axisof the plunger comprises (FIGS. 1 and 2) a keyway 15 in the plunger intowhich a small tab 21 projects, tab 21 being part of the contact panel.

It will be apparent that a variety of switching connections may be madeto the contact array shown, one of the simplest being thecross-connection of adjacent contact fingers by jumpers such as thatshown at 39, whereby the two inner contacts 40 will be cross-connectedwhen the plunger is elevated, and the two outer contacts 41 will becross-connected when the plunger is pulled in and thecorresponding'wiper fingers lodged thereon. Or, in another switchingarrangement, flexible conductors such as that at 44 may be connected bysoldering to the desired contact fingers.

In cases where the current to be carried by the contact system is highenough to cause objectionable arcing and carbonization or like resultantdeposits between the stationary contacts along each radial path, thearrangement shown in FIG. 5 may be employed to cause the spring contactfingers to provide another motion component which will move the contactsupwardly away from their stationary contacts concurrently with theradial advance of the wiper as it leaves one contact for engagement withanother. In this arrangement, a lifting means in the preferred form of asmall protuberance 46 is molded into the contact panel 18X betweensuccessive radiallyaligned contacts in such size and position as tocause the advancing contact portion of the finger 32X to rise upwardlyfrom the stationary contact areas and descend downwardly onto the nextsuch area, or conversely in the reverse movements of the wipers, e.g.FIG. 5 from 19 to 20 or vice versa.

While many contact arrangements have been employed in the past inconjunction with solenoids having plungers adapted to move radiallyprojecting contacts, no simple system is known which succeeds inconverting the linear displacement of the moving contact into alaterally, radial gliding movement of appreciable magnitude in which thecontacting action is either wholly a wiping action or a compound motionboth radial and tactile, as in the case of the lifting contact motion ofFIG. 5.

The improvements are not confined to the foregoing constructiondescribed by way of illustration, but may take other forms within thescope of the invention as defined by the appended claims. For example,the array of wiper fingers may be held stationary and the contact panelmade to move relative thereto. Likewise, a single solenoid may beemployed to drive more than one array of movable contact fingersrelative to an appertaining panel of stationary contacts.

We claim:

1. In a relay, a contact panel having at least two concentricallyarranged rings of contacts adapted to be connected and disconnected fromassociated circuit connections; a plunger movable linearly and centrallyof said rings of contacts along the axis of concentricity thereof;electromagnetic means for reciprocating said plunger, and contact meanscarried by said plunger circumambiently thereof and comprising flexiblespring fingers each having a free end portion projecting toward theplane of said panel at an angle such that on movement of the plunger apredetermined amount in a direction to displace said contacting free endportion toward the panel, said contacting portions will glide along thesurface of the panel in a direction generally radially outward from theplunger for wiping contact engagement with contact means in said rings.

2. Contact means for use in switching devices, relays, and the like, andcomprising a flat insulating panel, a drive member movable along an axiswhich is substantially at right angles to the plane of the panel, meansfor reciprocating said drive member between predetermined working limitsrelative to the panel, elongated spring contact fingers each attached atone upper end portion remote from said panel to an insulating membercarried by said drive member and each at spaced positions around saiddrive member, each finger having a portion projecting toward the panelin the general direction of movement of the drive member, and each saidfinger portion terminating in a contact portion angularly disposed tobear against said panel and glide along the latter in a generaldirection radially outward from said axis responsive to a predeterminedamount of movement of the drive member in the direction toward thepanel; and contact means carried on said panel at positions about saidaxis and lying in the path of radial gliding movement of one of saidfingers to be engaged and disengaged by the latter responsive toreciprocatory movement of the drive member.

3. In a contact system, a linearly reciprocable actuating member, anarray of elongated spring finger contacts arranged about the axis ofmovement of said actuating member and connected thereto forreciprocatory movement therewith, said finger contacts each having aportion extending generally in the direction of such movement andconverging into another portion directed outwardly away from said axisand terminating in a free contacting end portion including a glidingsurface, together with means providing an insulating gliding surfacelying in a plane at right angles to said axis in confrontation with saidfree contacting end portions and engaged thereby and serving to deflectsaid end portions on advance of the same in the direction against saidsurface responsive to operation of said actuating member accordingly,whereby the contact fingers are flexed sufficiently to cause saidcontacting end portions thereof to glide radially away from said axisand wipe along radial paths on said surface; and stationary contactmeans arranged on said surface in the path of radial gliding movement ofsaid contacting end portions for engagement and disengagement by thelatter responsive to a predetermined amount of reciprocatorydisplacement of said actuating member.

4. In a contact system according to claim 3, the further provision thatsaid stationary contact means includes at least two stationary contactareas spaced apart along a radius to said axis and lying in the path ofgliding travel of an appertaining one of said contact end portions so asto be individually engaged and disengaged in succession thereby, andsaid areas are separated by a non-conductive protuberance rising abovesaid surface in a manner to cause said free contacting end portion ofthe appertaining contact finger to be displaced in a sense laterallyaway from an adjacent one of said areas while gliding toward or awayfrom the other of said areas.

5. A relay comprising a substantially linearly-reciprocable operatingmember; stationary contact means arranged in a plane normal to the axisof reciprocation of said operating member and lying along a path whichis disposed radially of said axis in said plane; movable contact meansincluding at least one elongated spring contact finger and meansconnecting one end region thereof for movement with said operatingmember so that the major lengthwise portion of said finger moves backand forth in approximate parallelism with said axis and operating membertoward and away from said plane, said finger having an opposite endportion biased outwardly in an approximately radial sense from said axisfor engagement with said contact means to glide thereon radially of saidaxis responsive to linear reciprocation of said operating member; andelectromagnetic means for reciprocating said operating member.

References Cited by the Examiner UNITED STATES PATENTS 1,305,970 6/1919Kennedy 200104 X 2,162,528 6/1939 Curtiss 20016 BERNARD A. GILHEANY,Primary Examiner.

1. IN A RELAY, A CONTACT PANEL HAVING AT LEAST TWO CONCENTRICALLYARRANGED RINGS OF CONTACTS ADAPTED TO BE CONNECTED AND DISCONNECTED FROMASSOCIATED CIRCUIT CONNECTIONS; A PLUNGER MOVABLE LINEARLY AND CENTRALLYOF SAID RINGS OF CONTACTS ALONG THE AXIS OF CONCENTRICITY THEREOF;ELECTROMAGNETIC MEANS FOR RECIPROCATING SAID PLUNGER, AND CONTACT MEANSCARRIED BY SAID PLUNGER CIRCUMAMBIENTLY THEREOF AND COMPRISING FLEXIBLESPRING FINGERS EACH HAVING A FREE END PORTION PROJECTING TOWARD THEPLANE OF SAID PANEL AT AN ANGLE SUCH THAT ON MOVEMENT OF THE PLUNGER APREDETERMINED AMOUNT IN A DIRECTION TO DISPLACE SAID CONTACTING FREE ENDPORTION TOWARD THE PANEL, SAID CONTACTING PORTIONS WILL GLIDE ALONG THESURFACE OF THE PANEL IN A DIRECTION GENERALLY RADIALLY OUTWARD FROM THEPLUNGER FOR WIPING CONTACT ENGAGEMENT WITH CONTACT MEANS IN SAID RINGS.